1. Field of the Invention
The present invention is generally related to a bow string release and is specifically directed to a release having a floating jaw and a free floating trigger with a force adjustment mechanism.
2. Description of the Prior Art
Mechanical archery bow string releases have become increasingly popular in recent years because they provide uniform control of the bow string and increase accuracy by effecting the consistent, controlled release of the arrow. Bow string releases are typically used to maintain the bow string in a cocked position in which the bow string is flexed against the tension of the bow for propelling the arrow supported on the bow string.
When a drawn arrow is released from a release mechanism, the release is usually relatively rapid and at a point approximately in line with the centerline of the bow so that the bow string delivers most of its thrust directly along the major axis of the arrow. When tabs or fingers are used to release a bow string, the bow string tends to roll off the fingers or tab and be deflected sideways during release such that the bow string follows a serpentine path, failing to maximize energy delivery directly along the major axis of the arrow.
The arrow itself is generally comprised of a shaft with a point mounted on one end and a nook mounted on the opposite end. A standard arrow neck has a bow string receiving groove or notch defined by spaced apart legs extending from a base. The neck is configured to receive a bow string and insure stability of the arrow when the bow string is drawn and released. When an arrow is loaded on a bow in this manner, the legs of the arrow neck extend beyond the bow string toward the archer such that and arrow can rotate about the bow string. When engaging the bow string, the neck is preferably seated at or near the mid-pint of the bow string to insure that the flight of the arrow is as true as possible.
The majority of the bow string releases have a body or casing which houses the sear and trigger mechanisms. The body is typically a cylindrical or rectangular design with the pivotable jaws of the sear mechanism positioned at one end and a trigger located along the length of the body. The release employs a trigger mechanism to activate the bow string retaining and release mechanism. The jaws and trigger mechanism of the bow string release are traditionally secured to the body with linkages or pins, which serve as a pivot mechanism for the jaws and trigger.
U.S. Pat. No. 5,596,977 describes a bow string release having a cylindrical body housing a trigger mechanism, release mechanism and jaws, wherein pins are used to attach each element to the body and the pins also serve as a pivot for the jaws. The release is composed of a cylindrical body with the jaw mechanism containing one fixed jaw and one pivotal jaw. The jaws pivot action is supported by a pin that extends transversely through the cylindrical body. The jaw employs an additional pin, located on the rearward end, away from the bow string, to anchor the jaw to the body when the jaw pivots. The trigger mechanism is located within the cylindrical body with the finger enabling trigger located along the body on the same side as the pivotable jaw. The '977 patent further describes a trigger mechanism, wherein the trigger pivots about a pin that transverses the cylindrical body. The pin permits the finger engageable trigger to pivot and thereby engage the release mechanism.
The repeated use of a bow string release may wear down the pivot pins resulting in a pin that either does not pivot, which is undesirable. The use of pins to provide a pivot point is especially undesirable under conditions in which bow string releases are typically used, where the environment may include rain, snow, water, mud or other debris that could clog, disable or otherwise hinder pivot pin based releases because the pivot pins are not protected from the environment by the body therefore they are susceptible to environmental conditions. The integration of the pivot pin into the body and the sear mechanism may make the replacement of the jaws more difficult if not impossible.
Bow string releases may also contain a trigger adjustment mechanism which permits the control of the trigger pressure. Trigger adjustment mechanisms usually operate by changing the position of one element of the release mechanism in relation to another and are usually dependent on changing the position of an element, which changes the contact angles, which in turn changes the pressure required to operate the trigger.
A trigger adjustment mechanism can be found in U.S. Pat. No. 5,596,977. The amount of force necessary to be exerted on the trigger in order to release the pivot jaw is controlled by the position of the trigger mechanism which is controlled by a set screw.
It has been found that many commercial bow string releases, including a release referred to as a Tru-Ball “Tornado” release, “load up” severely as pulling force on the bow string is increased. “Loading up” is a phenomenon whereby the force required of the archer to pull the trigger and release the bow string increases as the effective draw weight of the bow increases. Thus, at higher effective draw weights, the archer must pull harder on the trigger, perhaps causing a decrease in sensitivity and performance. A harder trigger pull may also cause a jerking trigger release motion, causing erratic arrow flight.
There are two common trigger sensitivity adjustment mechanisms used widely. In one mechanism, the depth of engagement of sear elements is varied. This affects trigger pull length, also known as trigger travel distance, and indirectly affects pull force required by making the trigger travel farther to disengage the sear, which in turn increases the sliding friction. An example of this mechanism is U.S. Pat. No. 5,680,851 to Summers.
Another mechanism is a single roller on one sear element, sear element, typically mounted on one jaw, positioned in an angled slot in the other sear element, typically a slot in the trigger. Examples include a release known as the Scott Caliper release. In this mechanism, a roller is used to reduce friction between the sear elements. Adjustment is related to the positioning of a roller's center in relation to the edge of the angled slot. This limits the upper end range of trigger force required due to the rolling force in the slot. At the lower end of the pull force range, the roller center is balanced on or just outside the slot edge. If the roller center is outside the slot edge, the release will not stay closed during bow draw unless a force is applied to overcome the center over the edge condition created.
The set screw sets the sear at a distance so that the roller on the pivot jaw resists movement thus resulting in the need to increase the pressure necessary to engage the roller and move the pivotable jaw. The set screw can also set the sear distance to reduce the pressure necessary for the trigger to engage the roller and move the pivotable jaw.
The major drawbacks to some prior art systems of trigger adjustment is to control trigger pressure you must control trigger travel which requires the movement of the sears within the release mechanism, which in turn requires the adjustment of screws housed in the body or release mechanism. These screws are difficult to reach for adjustment and typically require special tools. Additionally, the screws do not have a mechanism that will enable one to calibrate or predict the level of trigger force.
The necessity of using the screw and/or special tools may make it difficult or impossible to adjust trigger pressure in the field where the screw may be too small to adjust or the environment may prevent the use of tools to adjust the trigger pressure. The tool as a separate element, the piece may be lost or dropped, rendering the trigger force adjusting mechanism virtually unusable.
Furthermore, as described above, the environments in which a bow string release device are typically may further frustrate use of a tool/screw configuration of the Scott patents, rendering the adjustment mechanism difficult to manipulate. For example, a gloved archer may have difficulty manipulating the small screw of the Scott patent, or debris may clog the holes used to adjust the trigger pressure.